EDK: Move {platform_handle,scoped_platform_handle}.* to //mojo/edk/platform.

shell/context.cc

Index: shell/context.cc
diff --git a/shell/context.cc b/shell/context.cc
index 3ecfa97b2b399755562fdfd4bd8719711cb7ce5c..de76e223b959fba622a1a9280fc3e48355c9ada8 100644
--- a/shell/context.cc
+++ b/shell/context.cc
@@ -319,7 +319,7 @@ bool Context::InitWithPaths(
   mojo::embedder::InitIPCSupport(mojo::embedder::ProcessType::MASTER,
                                  task_runners_->shell_runner().Clone(), this,
                                  task_runners_->io_runner().Clone(),
-                                 mojo::embedder::ScopedPlatformHandle());
+                                 mojo::platform::ScopedPlatformHandle());
 
   scoped_ptr<NativeRunnerFactory> runner_factory;
   if (command_line.HasSwitch(switches::kEnableMultiprocess))